Apparatus and process for stacking printed material with alternating edge orientation

ABSTRACT

A disk stacker system for delivering selectively inverted substrate assemblies into a receiving tray. By alternating inverted with non-inverted substrate assemblies or otherwise grouping inverted and non-inverted substrate assemblies, handling of folded printed material is made more efficient and packing of the folded printed material is made more dense and efficient. The disk stacker system operates by delivering selected substrate assemblies directly to the output tray and bypassing the disk stacker inverting apparatus and by delivering other substrate assemblies to the disk stacker apparatus for inversion prior to delivery to the output tray.

FIELD OF THE INVENTION

[0001] The field of the invention is finishing operations for printed material finished into assemblies of substrates such as booklets, newspapers, or similar compiled sets of substrate sheets. More particularly, the field of the invention relates to finishing equipment for stacking booklets and other printed articles comprised of folded substrates in an optimally compressed manner, especially when such booklets or folded articles are printed with digital printing systems such as electrophotographic printers. Although the invention will operate with both folded and unfolded assemblies of substrates, the advantages of the invention are apparent when performing finishing operations upon folded substrate materials.

BACKGROUND AND SUMMARY

[0002] very common form of printed matter is booklets comprised of folded sheets. Many such booklets are stapled, stitched, or otherwise bound along the fold and sometimes covered with a soft cover comprised of somewhat heavier substrate stock than the interior printed pages. Playbills, advertising booklets, mail order catalogues, many magazines, and many other printed articles are printed and bound in this manner. Other forms of printed material comprise assemblies of folded pages, or substrates, such as newspapers, which are folded but not bound.

[0003] Referring to FIGS. 1 and 2, a problem common to such folded printed materials is that a bulge occurs proximate to the folded edge of the printed assembly. The fold results because molecules or fibers within printed substrates such as plastic and paper retain some resistance to the fold. The result is that when such folded assemblies of substrates are stacked vertically as shown in FIG. 1, the side 11 of the stack containing the folded edges typically rises significantly higher than the side 12 having unfolded edges. If the stack is not contained as in a box, then the scene exemplified by FIG. 2 is common. Most household members are probably familiar with the situation shown in FIG. 2 when attempting to stack used newspapers.

[0004] One alternative to alleviate the problems shown in FIGS. 1 and 2 is shown in FIG. 3. In this solution, vertical stacks are avoided, and folded printed matter is partially overlaid on a planer surface such as a conveyor belt. Many newspaper publishing operations convey papers in this matter to their packaging and distribution operations. Of course, such planer surfaces occupy significant floor space and are impractical in most printing environments other than commercial print shops.

[0005] It would be advantageous to have an apparatus and method for vertically stacking folded printed matter in a manner that avoids the uneven stacks shown in FIGS. 1 and 2. It would be further advantageous if such apparatus and method required a relatively small footprint and relatively inexpensive equipment.

[0006] One aspect of the invention is a disk stacker system for selectively inverting substrate assemblies, comprising: a rotatable disk stacker having a slot for receiving a compiled assembly of substrates; a tray for receiving a plurality of substrate assemblies; and an apparatus for feeding the substrate assembly, said feeding apparatus having a first mode and a second mode wherein, in the first mode, said apparatus cooperates with the rotatable disk to feed the substrate assembly into the receiving slot of the rotatable disk stacker and, in the second mode, said apparatus feeds the substrate assembly to the tray without feeding the substrate assembly to the receiving slot of the rotatable disk stacker; wherein, in the first mode, after the substrate assembly is fed into the receiving slot of the rotatable disk stacker, the rotatable disk stacker rotates with the substrate assembly in its receiving slot and deposits the substrate assembly onto the tray in an inverted orientation; and wherein, in the second mode wherein the substrate assembly is fed to the tray without entering the receiving slot, the substrate assembly is delivered to the tray in an non-inverted orientation.

[0007] Another aspect of the invention is a printer system for printing and compiling a substrate assembly, said printer comprising: a rotatable disk stacker having a slot for receiving a compiled assembly of substrates; a tray for receiving a plurality of substrate assemblies; and an apparatus for feeding the substrate assembly, said feeding apparatus having a first mode and a second mode wherein, in the first mode, said apparatus cooperates with the rotatable disk to feed the substrate assembly into the receiving slot of the rotatable disk stacker and, in the second mode, said apparatus feeds the substrate assembly to the tray without feeding the substrate assembly to the receiving slot of the rotatable disk stacker; wherein, in the first mode, after the substrate assembly is fed into the receiving slot of the rotatable disk stacker, the rotatable disk stacker rotates with the substrate assembly in its receiving slot and deposits the substrate assembly onto the tray in an inverted orientation; and wherein, in the second mode wherein the substrate assembly is fed to the tray without entering the receiving slot, the substrate assembly is delivered to the tray in an non-inverted orientation.

[0008] Yet another aspect of the invention is a process for selectively inverting substrate assemblies, comprising: feeding a substrate assembly to a rotatable disk stacker system; selecting between a first and a second mode, wherein the first mode comprises feeding the substrate assembly into a receiving slot of the rotatable disk stacker and the second mode comprises feeding the substrate assembly to a tray without feeding the substrate assembly to the receiving slot of the rotatable disk stacker; and wherein the first mode further comprises rotating the rotatable disk stacker with the substrate assembly in its slot and depositing the substrate assembly onto the tray in an inverted orientation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is a plane view of a stack of folded substrate assemblies stacked using apparatus of the prior art;

[0010]FIG. 2 is a plane view of a disordered stack of folded substrate assemblies stacked using apparatus of the prior art;

[0011]FIG. 3 is a plane view of an arrangement of folded substrate assemblies using apparatus of the prior art;

[0012]FIG. 4 is a plane view of a stack of folded substrate assemblies stacked using the present invention;

[0013]FIG. 5 is an elevated cross sectional view of one embodiment of the disk stacker system of the present invention when delivering a non-inverted substrate assembly to an output tray;

[0014]FIG. 6 is an elevated cross sectional view of the embodiment shown in FIG. 5 when inserting a substrate assembly into an inverting disk stacker apparatus;

[0015]FIG. 7 is a plane view of an alternate method of stacking folded substrate assemblies using the present invention;

[0016]FIG. 8 is an elevated cross sectional view of a second embodiment of the present invention.

DESCRIPTION

[0017] For a general understanding of the present invention, reference is made to the drawings. In the drawings, like reference numerals have been used throughout to designate identical elements.

[0018] An exemplary system comprising one embodiment of the present invention is a multifunctional printer with an attached finisher apparatus comprising the present invention. Multifunctional printers are well known in the art and may comprise print engines based upon liquid or solid ink jet, electrostatography such as electrophotography, and other imaging devices. The general principles of electrophotographic imaging are well known to many skilled in the art. Generally, the process of electrophotographic reproduction is initiated by substantially uniformly charging a photoreceptive member, followed by exposing a light image of an original document thereon. Exposing the charged photoreceptive member to a light image discharges a photoconductive surface layer in areas corresponding to non-image areas in the original document, while maintaining the charge on image areas for creating an electrostatic latent image of the original document on the photoreceptive member. This latent image is subsequently developed into a visible image by a process in which a charged developing material is deposited onto the photoconductive surface layer, such that the developing material is attracted to the charged image areas on the photoreceptive member. Thereafter, the developing material is transferred from the photoreceptive member to a copy sheet or some other image support substrate to which the image may be permanently affixed for producing a reproduction of the original document. In a final step in the process, the photoconductive surface layer of the photoreceptive member is cleaned to remove any residual developing material therefrom, in preparation for successive imaging cycles.

[0019] The above described electrophotographic reproduction process is well known and is useful for both digital copying and printing as well as for light lens copying from an original. In many of these applications, the process described above operates to form a latent image on an imaging member by discharge of the charge in locations in which photons from a lens, laser, or LED strike the photoreceptor. Such printing processes typically develop toner on the discharged area, known as DAD, or “write black” systems. Light lens generated image systems typically develop toner on the charged areas, known as CAD, or “write white” systems. Embodiments of the present invention apply to both DAD and CAD systems. Since electrophotographic imaging technology is so well known, further description is not necessary. See, for reference, for example, U.S. Pat. No. 6,069,624 issued to Dash, et al. and U.S. Pat. No. 5,687,297 issued to Coonan et al., both of which are hereby incorporated herein by reference.

[0020] With reference now to FIG. 4, a desired method of stacking folded assemblies of printed substrates is shown. This neat stack of printed substrates may be the output of a multifunctional printer as described above or may be the output of any other print method, including without limitation, offset lithography, silk screen, liquid or solid ink jet, etc. Also, the output shown in FIG. 4 may be received in the schematically shown bin directly from the printer or press or may arrive from any variety of intermediate finishing equipment. The result of the invention, as shown in FIG. 4, is a neat stack of folded assemblies of printed substrates in which the folded edges labeled A alternate with the unfolded edges B.

[0021] One embodiment of the present invention that accomplishes the result shown in FIG. 4 is shown in FIG. 5. This embodiment of the invention borrows from the two decades of experience with single sheet disk inverter apparatus. Such experience is exemplified by U.S. Pat. No. 4,431,177, issued to J. Beery et al., U.S. Pat. No. 5,065,996 issued to McGraw et al., U.S. Pat. No. 5,409,202, issued to Naramore et al., U.S. Pat. No. 5,409,201, issued to Naramore et al., and U.S. Pat. No. 5,551,681, issued to Ferrara. As noted in Ferrara, “conventional disk stackers only invert one single sheet at a time” U.S. Pat. No. 5,551,681, column 1, lines 54-56. Ferrara is the exception and describes a disk stacker that compiles a stack of sheets through use of a disk within a disk arrangement. Ferrara and other disk stackers provide for stapling and other finishing processes after copy substrates enter the disk stacker. See FIG. 11 of Ferrarra, U.S. Pat. No. 5,551,681. See also, U.S. Pat. No. 5,409,202, issued to Naramore et al. Each of these patents are hereby incorporated herein by reference in their entirety. Each of the cited patents and others in the prior art provide for disk stackers that invert and stack sheets in preparation for finishing operations of the compiled stack. None provide for inverting and stacking of assemblies of sheets that already have been finished.

[0022] Referring to FIG. 5, folded substrate stacker system 20 is shown. Beginning from left to right, folded assembly 15 approaches stacker system 20 after having been folded and otherwise finished. Such finishing may include binding by staples, glue, or other binding means or such finishing may simply comprise folding operations. Of course, it is apparent that system 20 will also work with unfolded substrate assemblies, yet the primary purpose for which system 20 is expected to be used is in relation to folded assemblies of substrates. Upon entering the mouth of channel 23, substrate assembly 15 is gripped and pushed forward by drive wheels 21 and 22. At least one of drive wheels 21 and 22 are slidably held in place in order to adjust to varying thicknesses between different substrate assemblies 15 and, optionally, between the leading and trailing edges of each substrate assembly 15. Such slidable mounting of one or both wheels 21 and 22 may be accomplished by mounting the applicable wheel within a slide track and attaching biasing springs to urge the applicable wheel toward channel 23. For wheels such as 21 which are above channel 23, gravity may provide sufficient biasing.

[0023] As shown in FIG. 5, it is anticipated that most substrate assemblies will enter channel 23 with folded edge first. This arrangement inhibits outer sheets of substrate assembly 15 from getting wrinkled, folded, or otherwise damaged by the apparatus within system 20. This arrangement also minimizes the possibility of a jam occurring because one of more sheets become caught in the apparatus. It is also possible, however, to operate system 20 by having substrate assembly 15 lead with its unbound and unfolded edge.

[0024] After drive wheels 21 and 22 urge substrate assembly 15 further into channel 23, leading edge sensor 24 detects the leading edge of substrate assembly 15. Sensor 24 may comprise any number of well known detector technologies, including a simple assembly of an LED light source and a light detector spaced apart on opposite sides of channel 23. As substrate assembly 15 passes sensor 24, it blocks light from the light detector. Sensor 24 then sends a positive leading edge detection signal to the controller 29 for system 20. In this manner, sequence timing within system 20 can be maintained and parts activated to achieve the desired result. As shown in FIG. 5, substrate assembly 15 passes sensor 24 and next encounters drive wheels 25 and 26. These drive wheels function much like drive wheels 21 and 22, and the same or similar motor apparatus, mounting, and biasing may be used for drive wheels 25 and 26 as used for 21 and 22.

[0025] In FIG. 5, substrate assembly 16 has preceded assembly substrate 15 down channel 23 and is shown being driven, folded-edge first, into bin 27. Bin 27 is shown as a box having left and right sides but may be a simple tray for receiving the substrate assembly. Disk stacker 30 is shown in its by-pass position. In this position, disk stacker 30 has been rotated such that its gripping finger 33 is turned away from channel 23 and away from substrate assembly 16. Non-gripping surface 32 of disk stacker 30 is turned toward channel 23 and provides a rounded surface, along with drive wheel 26, for guiding substrate assembly 16 toward and then out of channel mouth 28 without inversion. The result is that substrate assembly 16 falls into bin 27 oriented with its bound or folded edge removed away from system 20.

[0026] Referring to FIG. 6, operation of disk stacker 30 is shown. In response from signals from the system controller, disk stacker 30 has been rotated such that finger 33 blocks channel mouth 28. As drive wheels urge substrate assembly 15 forward, finger 33 diverts the leading edge of such substrate assembly into slot 31 of disk stacker 30. Substrate assembly 15 is then urged forward into slot 31 until its leading edge contacts stop 34. As is conventional with disk stackers, sensors detect when substrate assembly 15 makes contact with stop 34, and disk stacker 30 is then rotated back to its starting position shown in FIG. 5. Such sensors are conventional in the art. Among the alternatives are pressure sensors placed on stop 34 itself or release mechanisms that engage disk stacker 30 once continued drive motion by drive wheels 25 and 26 begin forcing rotation of disk stacker 30 after substrate assembly 15 abuts stop 34. A method for removing substrate assembly 15 from finger 33 is for substrate assembly 15 to encounter a stop as disk stacker 30 continues to rotate. Regardless of the method to begin rotation of disk assembly 30 or to free substrate assemblies from finger 33, the result is that substrate assembly 15 is flipped into an inverted position onto the top of the stack in bin 27. This inversion and stacking result due to rotation of a disk stacker is well known to those skilled in the relevant disk stacker arts. The ability to perform this operation upon substrate assemblies rather than single sheets is novel as is the ability to alternate inversion and non-inversion operations. The stack of substrate assemblies that results is easier to handle and takes less volume.

[0027] Turning to FIG. 7, another variety of stacking is shown. In this embodiment, the same level and efficient stack of substrate assemblies has been achieved. Instead of alternating the inversion operation, a first bundle 41 of substrate assemblies has been placed in bin 27 in an inverted orientation and a second bundle 42 has been stacked on top of bundle 41 in an un-inverted orientation. It is believed that this arrangement may often facilitate future handling of the substrate assemblies since an entire bundle can be lifted out of a bin or box in the same orientation, and a user need not reorient each compilation for handling. For instance, playbills arranged in this manner may be easier for ushers to handle than a stack in which each playbill is placed in an alternating orientation.

[0028] The controller 29 for stacker system 30 controls whether substrate assemblies are stacked in alternating copies, alternating groups or any other arrangement. In the event that a user desires all substrate assemblies to be loaded into bin 27 with all cover pages up or all cover pages down, then the controller 29 may coordinate with a printer controller (not shown) such that substrate assemblies such as 15 and 16 are printed cover page up and cover page down in alternating fashion that corresponds to the manner in which each such compilation will be stacked in bin 27.

[0029] Referring now to FIG. 8, a disk stacker system 50 is shown that is capable of higher through put speeds than the disk stacker system 30 shown in FIGS. 5 and 6. In this system 50, disk stacker 60 has two sets of fingers, 63 and 64, located on opposing sides of disk 60.. Drive wheels 21, 22, 25, and 26 serve the same function as described in relation to FIGS. 5 and 6 as does bin 27. In the middle of channel 23, however, is pivotally mounted diverter gate 68, shown in both of its operable positions. Such diverter gates are well known to those skilled in the relevant arts. See, for example, U.S. Pat. No. 4,712,785 issued to Stemmle; U.S. Pat. No. 5,303,017 issued to Smith; and U.S. Pat. No. 5,065,996, issued to McGraw et al. In FIG. 8, substrate assembly 17 has been directed down channel 23 toward disk stacker 60. Disk stacker 60 operates similarly to disk stacker 30 shown in FIGS. 5 and 6, and operates to invert and stack substrate assembly 17 into bin 27. Once substrate assembly 17 has passed diverter gate 68, controller 29 directs a pivot mechanism to switch diverter gate 68 to its alternate position. Substrate assembly 18 will be diverted into alternate channel 69. Alternate channel 69 carries substrate assembly 18 around disk stacker 60 and toward drive wheels 66 and 67. Drive wheels 66 and 67 urge substrate assembly 18 into bin 27. Pivotally mounted bail wire 65 is positioned to assist substrate assembly 18 to fall into bin 27 in an un-inverted, controlled fashion.

[0030] The stacking result of the apparatus in FIG. 8 is the same as achievable with the system shown in FIGS. 5 and 6. One skilled in the art will recognize that some of the features in FIGS. 5 and 6 can be interchanged with features shown in FIG. 8 and vice versa. Specifically, a double set of fingers, a diverter gate, an alternate channel, and a bail wire guide may individually be integrated into stacker system 20 shown in FIGS. 5 and 6. Similarly, a stacker disk with a single finger and a single channel with or without a diverter gate can be integrated into stacker system 50 shown in FIG. 8. Other variations are also possible.

[0031] In sum, an improved disk stacker system has been disclosed that provides for inversion of substrates, especially folded substrates such as booklets and newspapers. When such inversion is alternated between compiled sets or between groups of compiled sets, then stacking efficiency and order are greatly improved over the prior art.

[0032] While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or may be presently unforeseen may arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they may be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents. 

1. A disk stacker system for selectively inverting substrate assemblies, comprising: a rotatable disk stacker having a slot for receiving a compiled assembly of substrates; a tray for receiving a plurality of substrate assemblies; and an apparatus for feeding the substrate assembly, said feeding apparatus having a first mode and a second mode wherein, in the first mode, said apparatus cooperates with the rotatable disk to feed the substrate assembly into the receiving slot of the rotatable disk stacker and, in the second mode, said apparatus feeds the substrate assembly to the tray without feeding the substrate assembly to the receiving slot of the rotatable disk stacker; wherein, in the first mode, after the substrate assembly is fed into the receiving slot of the rotatable disk stacker, the rotatable disk stacker rotates with the substrate assembly in its receiving slot and deposits the substrate assembly onto the tray in an inverted orientation; and wherein, in the second mode wherein the substrate assembly is fed to the tray without entering the receiving slot, the substrate assembly is delivered to the tray in an un-inverted orientation.
 2. The disk stacker system of claim 1, wherein the feeding apparatus comprises a first channel for bypassing the rotatable disk stacker and a second channel for feeding the substrate assembly to the slot of the rotatable disk stacker.
 3. The disk stacker system of claim 1, further comprising a diverter gate having a first position wherein the first mode is selected and a second position wherein the second mode is selected.
 4. The disk stacker system of claim 3, wherein the feeding apparatus comprises a single channel and wherein the diverter gate operates in the first mode by diverting the substrate assembly into the receiving slot of the rotatable disk.
 5. The disk stacker system of claim 3, wherein: the feeding apparatus comprises a first a second channel for feeding the substrate assembly to the slot of the rotatable disk stacker channel and a second channel for bypassing the rotatable disk stacker; and the first position of the diverter gate guides the substrate assembly to the first channel and the second position of the diverter gate guides the substrate assembly to the second channel.
 6. The disk stacker system of claim 1, wherein the first mode operates by rotating the receiving slot of the rotatable disk stacker to intercept the substrate assembly within the feeding apparatus.
 7. The disk stacker system of claim 1, wherein the rotatable disk stacker comprises a plurality of receiving slots.
 8. The disk stacker system of claim 1, wherein the substrate assembly has a thickness and wherein the feeding apparatus further comprises: a slidably mounted drive wheel for contacting the substrate assembly and urging the substrate assembly toward the tray, said drive wheel being free to slide within its mount to accommodate the thickness of the substrate assembly; and a bias mechanism urging the drive wheel into contact with the substrate assembly as the drive wheel urges the substrate assembly toward the tray.
 9. The disk stacker system of claim 8, further comprising a first slidably mounted drive wheel positioned proximate to the entrance to the feeding apparatus and a second slidably mounted drive wheel positioned proximate to the exit from the feeding apparatus.
 10. The disk stacker system of claim 1, further comprising a sensor for detecting the leading edge of the substrate assembly.
 11. The disk stacker system of claim 1, further comprising a sensor for detecting the trailing edge of the substrate assembly.
 12. The disk stacker system of claim 1, further comprising a bailing mechanism for guiding the substrate assembly onto the tray.
 13. A printer system for printing and compiling a substrate assembly, said printer comprising: a rotatable disk stacker having a slot for receiving a compiled assembly of substrates; a tray for receiving a plurality of substrate assemblies; and an apparatus for feeding the substrate assembly, said feeding apparatus having a first mode and a second mode wherein, in the first mode, said apparatus cooperates with the rotatable disk to feed the substrate assembly into the receiving slot of the rotatable disk stacker and, in the second mode, said apparatus feeds the substrate assembly to the tray without feeding the substrate assembly to the receiving slot of the rotatable disk stacker; wherein, in the first mode, after the substrate assembly is fed into the receiving slot of the rotatable disk stacker, the rotatable disk stacker rotates with the substrate assembly in its receiving slot and deposits the substrate assembly onto the tray in an inverted orientation; and wherein, in the second mode wherein the substrate assembly is fed to the tray without entering the receiving slot, the substrate assembly is delivered to the tray in an non-inverted orientation.
 14. The printer system of claim 13, wherein the feeding apparatus comprises a first channel for bypassing the rotatable disk stacker and a second channel for feeding the substrate assembly to the slot of the rotatable disk stacker.
 15. The printer system of claim 13, further comprising a diverter gate having a first position wherein the first mode is selected and a second position wherein the second mode is selected.
 16. The printer system of claim 15, wherein the feeding apparatus comprises a single channel and wherein the diverter gate operates in the first mode by diverting the substrate assembly into the receiving slot of the rotatable disk.
 17. The printer system of claim 15, wherein: the feeding apparatus comprises a first a second channel for feeding the substrate assembly to the slot of the rotatable disk stacker channel and a second channel for bypassing the rotatable disk stacker; and the first position of the diverter gate guides the substrate assembly to the first channel and the second position of the diverter gate guides the substrate assembly to the second channel.
 18. The printer system of claim 13, wherein the first mode operates by rotating the receiving slot of the rotatable disk stacker to intercept the substrate assembly within the feeding apparatus.
 19. The printer system of claim 13, wherein the rotatable disk stacker comprises a plurality of receiving slots.
 20. The printer system of claim 13, wherein the substrate assembly has a thickness and wherein the feeding apparatus further comprises: a slidably mounted drive wheel for contacting the substrate assembly and urging the substrate assembly toward the tray, said drive wheel being free to slide within its mount to accommodate the thickness of the substrate assembly; and a bias mechanism urging the drive wheel into contact with the substrate assembly as the drive wheel urges the substrate assembly toward the tray.
 21. The printer system of claim 13, further comprising a sensor for detecting the leading edge of the substrate assembly.
 22. The printer system of claim 13, wherein the printer comprises an electrophotographic printer.
 23. A process for selectively inverting substrate assemblies, comprising: feeding a substrate assembly to a rotatable disk stacker system; selecting between a first and a second mode, wherein the first mode comprises feeding the substrate assembly into a receiving slot of the rotatable disk stacker and the second mode comprises feeding the substrate assembly to a tray without feeding the substrate assembly to the receiving slot of the rotatable disk stacker; and wherein the first mode further comprises rotating the rotatable disk stacker with the substrate assembly in its slot and depositing the substrate assembly onto the tray in an inverted orientation.
 24. The process of claim 23, wherein the first mode and the second mode are alternately selected for successive substrate assemblies.
 25. The process of claim 23, wherein the first mode is selected for a first grouping of successive substrate assemblies and the second mode is selected for a second grouping of successive substrate assemblies. 